Arthus-type panophthalmitis is an acute intraocular inflammatory condition which is produced in rats by injury of the lens following hyperimmunization using soluble rabbit lens crystallins. The onset of inflammation is rapid and the eyes progress to phthisis due to a severe granulomatous panophthalmitis in one week. This entity has been hypothesized to be a disease which is produced by circulating immune complex deposition. However, circulating immune complexes have never been measured in this experimental model. This project has been directed at the evaluation of humoral and cellular immunity in Arthus-type panophthalmitis to provide a better understanding of the general events of intraocular inflammatory disease. We determined that rats that develop this intraocular inflammation have no cell-mediated immunity to rat lens protein and have little to no cell-mediated responses to rabbit lens protein. However, they have markedly elevated titers of anti-rabbit lens crystallins. Elevated levels of circulating immune complexes were not detected in control animals but were detected in many animals that developed Arthus-type panophthalmitis. However, these circulating complexes were also detected in animals prior to lens injury when there was no intraocular inflammation and also in animals immunized with bovine serum albumin. Deposition of IgG and C3 was detected in the eyes of animals with Arthus-type panophthalmitis.